Além de receber eventos MIDI nõs podemos também enviar eventos MIDI para disparar e controlar hardware de sintetizadores externos, teclados e outros aparelho. O Sonic Pi fornece um conjunto completo de funções para enviar várias mensagens MIDI como:
midi_note_onmidi_note_offmidi_ccmidi_pitch_bendmidi_clock_tickTambém existem muitas outras mensagens MIDI suportadas - verifique a documentação da API para todas as outras funções que começam com midi_.
In order to send a MIDI message to an external device, we must first have connected it. Check out the subsection ‘Connecting a MIDI Controller’ in section 11.1 for further details. Note that if you’re using USB, connecting to a device which you’re sending to (rather than receiving from) is the same procedure. However, if you’re using the classic DIN connectors, make sure you connect to the MIDI out port of your computer. You should see your MIDI device listed in the preferences pane.
The many midi_* fns work just like play, sample and synth in that they send a message at the current (logical) time. For example, to spread out calls to the midi_* fns you need to use sleep just like you did with play. Let’s take a look:
midi_note_on :e3, 50This will send a MIDI note on event to the connected MIDI device with velocity 50. (Note that Sonic Pi will automatically convert notes in the form :e3 to their corresponding MIDI number such as 52 in this case.)
If your connected MIDI device is a synthesiser, you should be able to hear it playing a note. To disable it use midi_note_off:
midi_note_off :e3By default, Sonic Pi will send each MIDI message to all connected devices on all MIDI channels. This is to make it easy to work with a single connected device without having to configure anything. However, sometimes a MIDI device will treat MIDI channels in a special way (perhaps each note has a separate channel) and also you may wish to connect more than one MIDI device at the same time. In more complicated setups, you may wish to be more selective about which MIDI device receives which message(s) and on which channel.
We can specify which device to send to using the port: opt, using the device name as displayed in the preferences:
midi_note_on :e3, port: "moog_minitaur"We can also specify which channel to send to using the channel: opt (using a value in the range 1-16):
midi_note_on :e3, channel: 3Of course we can also specify both at the same time to send to a specific device on a specific channel:
midi_note_on :e3, port: "moog_minitaur", channel: 5Finally, a really fun thing to do is to connect the audio output of your MIDI synthesiser to one of the audio inputs of your soundcard. You can then control your synth with code using the midi_* fns and also manipulate the audio using live_audio and FX:
with_fx :reverb, room: 1 do
live_audio :moog
end
live_loop :moog_trigger do
midi (octs :e1, 3).tick, sustain: 0.1
sleep 0.125
end(The fn midi is available as a handy shortcut to sending both note on and note off events with a single command. Check out its documentation for further information).